Construction machinery field: In construction machinery, such as excavators, the piston rod plays an important transmission role. For example, in a certain factory, the piston rod of an excavator broke. Through macroscopic and microscopic fracture analysis, chemical composition analysis, metallographic microstructure analysis and other means, failure analysis was carried out. The results show that improper heat treatment process and rough machining tool marks at the transition fillet lead to premature multi-source fatigue fracture of the piston rod.

 

Cylinder field: The piston rod of a construction machinery cylinder had a one-time brittle fracture at the initial stage of use. The reasons for the fracture failure of the piston rod were analyzed through macroscopic analysis, chemical composition analysis, hardness test, fracture analysis and metallographic inspection. The results show that improper heat treatment process causes reticular ferrite and Widmanstatten structure in the piston rod, causing grain boundary embrittlement. Coupled with the high content of sulfide inclusions in the sample, the ability of the piston rod to bear alternating loads is reduced, and finally brittle fracture occurs.

 

Vehicle shock absorption system field: The vehicle shock absorption system is an important part in the vehicle's cushioning and shock absorption process. Its performance directly affects the ride comfort, handling stability and comfort of the whole vehicle, as well as the overall service life. Currently, cylindrical hydraulic shock absorbers are widely used on vehicles. The parts of the restoration valve system are sequentially assembled on the threaded rod at the end of the piston rod and connected together by nuts.